IGCSE Biology glossary
Binomial system
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
An internationally agreed system in which the scientific name of an organism is made up of two parts: the genus and the species.
What to include in an exam answer
Examiners pay for naming both parts (genus then species) and for knowing it is an internationally agreed system, so scientists worldwide use the same name. A frequent presentation mark: the genus starts with a capital letter and the species with a lower-case letter, and the name is written in italics (or underlined when handwritten). Getting the case or order wrong loses the convention mark.
Example in context
On naming conventions: 'In the binomial system the human is named Homo sapiens, where Homo is the genus and sapiens is the species, with the genus given a capital letter.'
Related syllabus topic
Characteristics & classification of living organisms